On this Thanksgiving Eve, many of us are preparing to gather around the centerpiece of this beloved tradition: food. Although no two Thanksgiving menus are exactly identical—regional fare such as sauerkraut and crab casserole have appeared on my family's dinner table—core components such as turkey, potatoes, cranberry sauce, and pumpkin pie are served in some variation.

Our annual observance of this holiday attaches a sense of continuity and ritual to Thanksgiving—but just how authentic is our present-day celebration? Did the English Pilgrims and Wampanoag really celebrate the First Thanksgiving with turkey and pumpkin pie on the fourth Thursday of November? And have Americans commemorated this event every year for nearly four centuries?

Historians believe the First Thanksgiving occurred sometime between September 21st and November 9th, which coincided with Keepunumuk, the Wampanoag time of harvest. The English colonists had just endured a very difficult first year in North America—only one-third of the original 150 who made the voyage on the Mayflower lived to experience the harvest feast. In celebration of the colonists' survival, which coincided with the harvest of native corn and the return of migratory birds to the Plymouth area, Plymouth Governor William Bradford invited an unspecified number of Wampanoag People "for three days of entertainment, feasting, and diplomacy."

By current standards, the bill of fare was likely lean and simple. Surviving documentation mentions only two food items (deer and wildfowl), and it provides no details about preparation or how much food people consumed. Although birds appeared to play a role in the original menu, turkey—the cornerstone of Thanksgiving feasts in present-day America—may not have been among the varieties on the Pilgrims’ table.

As for potatoes, the English and Wampanoag would not even have recognized them as food. The Smithsonian Magazine reports that "white potatoes, originating in South America, and sweet potatoes, from the Caribbean, had yet to infiltrate North America." They didn’t cover their meat in cranberry sauce, either—the concept of boiling cranberries and sugar didn’t enter English cuisine for another half century. And although the early settlers had pumpkins and squashes, the first recipes for pumpkin pie didn’t appear until later in the 17th century.

So how and when did Thanksgiving become an annual tradition? And who initiated the idea of turkey, mashed potatoes, and pumpkin pie? It all goes back to a Philadelphia woman named Sarah Josepha Hale, the editor of Godey’s Lady’s Book, and according to the Smithsonian, "a real trendsetter for running a household." In 1827, Hale initiated a lengthy campaign to petition the President of the United States for a national holiday to give thanks. After several fruitless decades, she successfully made her case to Abraham Lincoln, who thought that Hale’s idea would help unite the country during the Civil War. In 1863, Thanksgiving became a national holiday.

But Hale's influence didn’t end there; we also owe our traditional Thanksgiving menu to her. In between petitioning the presidents, she was publishing menus and working on a series of cookbooks for the holiday she'd hoped to create. Historian Kathleen Wall writes that "a lot of the food that we think of—roast turkey with sage dressing, creamed onions, mashed turnips, even some of the mashed potato dishes, which were kind of exotic then" had their roots in Hale’s publications. When Lincoln arrived at the White House, scores of housewives had already read Hale's recipes and were eager to prepare the dishes that Americans would forever associate with Thanksgiving.